Information on biological aspects of the finfish catches obtained in the survey of BIP Dr. E L Holmberg, conducted around Shag Rocks and the South Georgias Islands in April-May 2013, is presented. A total of 25 tows were taken, catches comprised sixteen finfish species, being Champsocephalus gunnari, Chaenocephalus aceratus, Notothenia rossii, Pseudochaenichthys georgianus, Patagonotothen brevicauda guntheri and Gobionotothen gibberifrons, the most frequents. The highest fish densities were found in the shelf of the South Georgias Islands. Total lengths ranged from 4 to 55 cm, 7 to 63 cm, 9 to 51 cm, 31 to 78 cm, 11 to 20 cm and 4 to 43 cm for C. gunnari, C. aceratus, P. georgianus, N. rossii, P. brevicauda guntheri and G. gibberifrons, respectively. Males and females showed a similar population structure, in a relation 1:1 in all the species analyzed.
Two length-weight relationships were estimated for C. gunnari and C. aceratus; for specimens below and above 11 cm TL. Statiscally significant differences were found between them (ANCOVA p<0.05). Length at first maturity (L50) was estimated in 26.87 cm for C. gunnari for the pooled data. No significant differences were found between males and females. Juveniles of several species were present in significant numbers.